The invention relates to a method for separating a useful layer, initially attached by a sacrificial layer to a layer forming a substrate, method comprising                at least partial etching of the sacrificial layer,        doping, before etching of the sacrificial layer, of at least a part of the surface of at least one of the layers in contact with the sacrificial layer and,        after etching of the sacrificial layer, a superficial etching phase of said surface so as to increase the roughness of the doped part of the surface.        